[Immunohistological study of eosinophilic infiltration of nasal polyps in aspirin-induced asthma].

It is well known that nasal polyps frequently develop in patients with aspirin-induced asthma, which is thought to be a non-atopic disease. We immunohistochemically examined the eosinophils infiltrating the nasal polyps in patients with aspirin-induced asthma. It has also been established that the monoclonal antibody EG1 reacts with both stored and secretion type ECP (eosinophil cationic protein), and that EG2 reacts only with the secretion type of ECP. EG2 positive cells may thus be considered to be activated eosinophils. Seven cases with nasal polyps associated with aspirin-induced asthma participated in our study. Blood eosinophilia was observed in all 7 cases, but 6 showed normal blood values IgE. Two reacted to house dust antigen, on skin tests and RAST. In the nasal polyps, many EG2 positive cells were observed. On serial sections, the number and distribution of EG1 and EG2 positive cells were almost equal. In the superficial lamina propria, extra-cellular release of ECP was noted. However, epithelial damage did not relate to the number of EG2 positive cells or the degree of extra-cellular EG2 release. In the deep lamina propria, slight extra-cellular ECP release was found. From these results, the eosinophils in nasal polyps accompanying aspirin-induced asthma were thought to be activated. Eosinophils seem to play an important role in the development of nasal polyps. However, tissue injury induced by eosinophils, was not be demonstrated in this study.